全文获取类型
收费全文 | 89篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 3篇 |
化学工业 | 6篇 |
金属工艺 | 7篇 |
机械仪表 | 41篇 |
能源动力 | 1篇 |
轻工业 | 16篇 |
无线电 | 6篇 |
一般工业技术 | 5篇 |
原子能技术 | 2篇 |
自动化技术 | 5篇 |
出版年
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 6篇 |
2012年 | 5篇 |
2011年 | 8篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 2篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1987年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有93条查询结果,搜索用时 15 毫秒
1.
艾叶精油化学成分研究 总被引:7,自引:1,他引:7
本文用水蒸气蒸馏法提取了不同产地艾叶精油,采用GC-MS技术分析了艾叶精油的化学成分。结果不同产地艾叶精油的质量收率为0.29%~0.56%,都含有特征成分:α-蒎烯、β-蒎烯、α-松油烯、γ-松油烯、桉叶素、蒿酮、蒿醇、2-环己烯-1-醇、樟脑、龙脑、4-松油醇、反式-石竹烯、丁子香酚。其中具有药效作用的成分有桉叶素(14.32%~26.12%,质量百分数,下同),樟脑(3.66%~14.97%)、龙脑(0.51%~10.53%)、甘菊环(0.00%~23.95%)等,有毒成分侧柏酮含量为0.32%~3.62%。 相似文献
2.
Young-Soo Seo Weui-Bong Jeong Wan-Suk Yoo Ho-Kyeong Jeong 《Journal of Mechanical Science and Technology》2005,19(2):625-633
A finite element vibration analysis of thin-watled cylindrical shells conveying fluid with uniform velocity is presented The
dynamic behavior of thin-walled shell is based on the Sanders’ theory and the fluid in cyhndrical shell is considered as inviscid
and incompressible so that it satisfies the Laplace’s equation A beam-like shell element is used to reduce the number of degrees-of-freedom
by restricting to the circumferential modes of cylindrical shell An estimation of frequency response function of the pipe
considering of the coupled effects of the internal fluid is presented A dynamic coupling condition of the interface between
the fluid and the structure is used The effective thickness of fluid according to circumferential modes is also discussed
The influence of fluid velocity on the frequency response function is illustrated and discussed The results by this method
are compared with published lesults and those by commercial tools 相似文献
3.
We propose a multipoint scanning dual‐detection confocal microscopy (MS‐DDCM) system for fast 3D volumetric measurements. Unlike conventional confocal microscopy, MS‐DDCM can accomplish surface profiling without axial scanning. Also, to rapidly obtain 2D images, the MS‐DDCM employs a multipoint scanning technique, with a digital micromirror device used to produce arrays of effective pinholes, which are then scanned. The MS‐DDCM is composed of two CCDs: one collects the conjugate images and the other collects nonconjugate images. The ratio of the axial response curves, measured by the two detectors, provides a linear relationship between the height of the sample surface and the ratio of the intensity signals. Furthermore, the difference between the two images results in enhanced contrast. The normalising effect of the MS‐DDCM provides accurate sample heights, even when the reflectance distribution of the surface varies. Experimental results confirmed that the MS‐DDCM achieved high‐speed surface profiling with improved image contrast capability. 相似文献
4.
Sintered silicon carbide (SiC) was etched by a dielectric barrier discharge source. A high voltage bipolar pulse was used with helium gas for the plasma generation. One stable filament plasma was generated and could be used for SiC etching. As the processing gas (NF3) mixing rate increased, the width and depth of the etching profile became narrower and deeper. The differentiated V–Q Lissajous method was used for measuring the capacitances (Ceq) of the electrode after the plasma turned on. The width of the etching profile was proportional to Ceq. As the current peak value Ismx of the substrate current increased, the volume removal rate of SiC increased. The etch depth was proportional to the ratio of Ismx to Ceq. Additionally, because of the different characteristics of the plasma disks on SiC substrate by the voltage polarity, the etching profile was unstable. However, in high NF3 mixing process, the etching profile became stable and deeper. 相似文献
5.
Jin-Rae?ChoEmail author Hyun-Sung?Jeong Wan-Suk?Yoo Sung-Woo?Shin 《Journal of Mechanical Science and Technology》2004,18(8):1327-1337
An efficient multi-objective optimization method is presented making use of neural network and a systematic satisficing trade-off
method (STOM), in order to simultaneously improve both maneuverability and durability of tire. Objective functions are defined
as follows: the sidewall-carcass tension distribution for the former performance while the belt-edge strain energy density
for the latter. A back-propagation neural network model approximates the objective functions to reduce the total CPU time
required for the sensitivity analysis using finite difference scheme. The satisficing trade-off process between the objective
functions showing the remarkably conflicting trends each other is systematically carried out according to our aspiration-level
adjustment procedure. The optimization procedure presented is illustrated through the optimum design simulation of a representative
automobile tire. The assessment of its numerical merit as well as the optimization results is also presented. 相似文献
6.
KWANG-HOON KONG SUNG-GUAN HONG SUN-YOUNG YOO KWANG-SOO LEE HA-HYUNG KIM 《Journal of Food Biochemistry》2004,28(6):500-512
A lectin gene homolog of Oryza sativa was successfully cloned and expressed in Escherichia coli. The deduced amino acid sequence of the protein product showed a significant similarity with known chitin‐binding lectins. Most of the recombinant lectin was found in an insoluble aggregated form as inclusion bodies and only a small part was in the culture medium in a soluble active form. Functional recombinant lectin was recovered from the inclusion bodies by solubilization with 8 M urea in Tris/HCl buffer, pH 7.0 and renaturation by 10‐fold dilution in the same buffer. The recombinant lectin with His‐tag was simply purified to homogeneity by the process of affinity chromatography and was obtained with a yield of 6–8 mg/L culture. The recombinant lectin was a homo‐dimer composed of 22 kDa. The hemagglutination activity of the recombinant lectin was optimal at pH 4.0–7.0 and it was very sensitive to inhibition by N‐acetylneuraminic acid and thyroglobulin. 相似文献
7.
Hee-Sik Kim Wan-Suk Lee Chi-Yong Ahn Byung-Hyuk Kim Jang-Eok Kim Hee-Mock Oh 《Korean Journal of Chemical Engineering》2010,27(6):1750-1754
In the Fenton reaction, degradation and dechlorination are directly affected by the concentrations of hydrogen peroxide and Fe3+. Although there is considerable research on the biodegradation of chlorinated compounds combined with the Fenton reaction, the kinetics of degradation and dechlorination of the reaction, with various concentrations of hydrogen peroxide and Fe3+, have been rarely investigated. Therefore, we investigated the degradation and dechlorination of PCE with various concentrations of hydrogen peroxide and Fe3+. The initial concentration of PCE (10 μM) decreased from a value of 8.9 μM (with 0.1 mM of hydrogen peroxide and 5 mM of Fe3+) to 1.1 μM (with 10 mM of hydrogen peroxide and 5 mM of Fe3+); the respective values for chloride ions produced were 0.9 and 21.6 μM. Also, the initial 10 μM of PCE decreased from 8.9 (with 0.1 mM of Fe3+ and 5 mM of hydrogen peroxide) to 2.2 μM (with 10mM of Fe3+ and 5 mM of hydrogen peroxide); the respective chloride ions produced were 0.7 and 14.5 μM. The logarithmic correlations between the degradation and dechlorination coefficients were 0.7682 and 0.7834 for concentrations of hydrogen peroxide and Fe3+, respectively. Both coefficients were used, from all possible cases, to derive six models which displayed both the ratio of degradation and dechlorination and the hydrogen peroxide and Fe3+ concentrations. The dechlorination of PCE could then be predicted with the model obtained by the coefficient with the concentration of hydrogen peroxide and Fe3+. The models could be applied to various Fenton reactions for optimization of degradation or dechlorination, such as biodegradation of PCE which is scarcely degraded by aerobic bacteria. 相似文献
8.
该文对利用感应耦合等离子体(ICP)刻蚀设备来制作图形化蓝宝石基底(PSS)的工艺控制进行了研究。在工艺制作过程中,选用了C轴(0001)取向的100 mm蓝宝石平片作为实验样品,通过光刻工艺和ICP刻蚀工艺控制,制作出了具有圆锥状图形结构的图形化蓝宝石基底。借助扫描电子显微镜,对该图形化蓝宝石基底进行了测量和分析。测量结果显示,基底表面上的单粒圆锥状图形结构的底部直径为(3.45±0.25) μm,刻蚀高度/深度为(1.75±0.25) μm,整个图形化蓝宝石基底成品片的均匀性控制在3%以内。 相似文献
9.
Virtual simulation is an economical and efficient method in mechanical system design. Numerical modeling of a spar platform, tethered by a mooring cable with a spherical joint is developed for the dyna... 相似文献
10.
Jae-Wook Lee Deuk-Man An Wan-Suk Yoo 《Journal of Mechanical Science and Technology》2011,25(5):1287-1296
In this study, the transient analysis of a cable unwinding from a cylindrical spool package is studied. Cables are withdrawn
with a constant velocity through a fixed point which is located along the axis of the package. When the cable is flown out
of the package, several dynamic forces, such as inertial force, Coriolis force, centrifugal force, tensile force, and fluid-resistance
force are acting on the cable. Consequently, the cable becomes to undergo very nonlinear and complex unwinding behavior which
is called unwinding balloon. In this paper, to prevent the problems during unwinding such as tangling or cutting, unwinding
behaviors of cables in transient state were derived and analyzed. First of all, the governing equations of motion of cables
unwinding from a cylindrical spool package were systematically derived using the extended Hamilton’s principles of an open
system in which mass is transported at each boundary. And the modified finite difference methods are suggested to solve the
derived nonlinear partial differential equations. Time responses of unwinding cables are calculated using Newmark time integration
methods. 相似文献